Scientists report1 a gradual decline in the prevalence of multi-drug resistant tuberculosis (MDR-TB) in south India from 8.4% in 2015 to 1.3% in 2018.
Individually, resistance to the two first-line anti-TB drugs — Rifampicin and Isoniazid — also declined from 2015 onwards and this may be pointing to the effectiveness of India's Revised National TB Control Program, according to the authors of the study.
Their study involved a retrospective analysis (for drug resistance) of 20, 245 specimens obtained from presumptive TB patients in the southern states of Tamil Nadu and Puducherry between 2013 to 2018. They also examined associations between age, gender, previous treatment/failure, HIV status, and drug resistance.
The researchers found a positive association of MDR-TB with the female gender and negative association with old age indicative of the mechanisms by which the immune system and sex hormones may be involved in the pathogenesis of MDR-TB. These aspects could be studied further for innovative approaches to target MDR-TB, the researchers say.
MDR-TB is strongly correlated with treatment failure and spreads through contact. There is an inherent male bias in the incidence of TB and post-pubertal females tend to mount a more robust immune response, the researchers say.
Although many studies have suggested that HIV (Human Immunodeficiency Virus) could augment the risk of MDR-TB, the authors say their study "using a reasonably large sample size, did not find evidence for this observation."
References
1. Shivekar, S. et al. Prevalence and factors associated with multidrug-resistant tuberculosis in South India. Sci. Rep. (2020) doi: s41598-020-74432-y
